ZLG Embedded Notes (Part 11) | Why is your network card not working properly? (Part 2)

This article discusses two special network card failure scenarios: low temperature operation and network freeze caused by signal interference. After many attempts, we found the root cause of the problem - the MDIO clock signal will produce glitches when it is low temperature or interfered, causing the register to write an incorrect value and put the PHY into an abnormal state. The solution is to connect a 22 ohm resistor in series at the MDC signal source end. In addition, we also discussed the importance of MDIO and its difference from I2C.